Fluid-pressure device.



R. LIEBAU. FLUID PRESSURE DEVICE.

ArPLIoATIoN FILED 11.3.25, 1910. nmsmwnn rma.

Patented Aug. 26, 1913.

2 SHEETS-SHEET 1.

WTNESSES:

R. LIEBAU.

FLUID PRESSURE DEVICE. APPLICATION FILED rms. 25, 1910. Mmnwnn rma. 1e,1913.

Patented Aug. 26, 1913.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

RICHARD LIEBA'U, 0F WATEBVLIET, NEW YORK, ASSIGNOB T0 THE WESTINGHOUSEAIR SPRING COMPANY, A CORPORATION OF PENNSYLVANIA.

FLUID-PRESSURE DEVICE.

Patented Aug. 26,1913.

Application filed February 25, 1910, Serial No. 545,956. RenewedFebruary 15, 1913. Serial No. 7-1r8,707.l

To all whom z't may concern.'

Be it known that I, RICHARD LIEBAU, a citizen of the United States, andresident of ratei-vliet, in the county of Albany and State of New York,have invented certain new and useful Improvements in Fluid- PressureDevices, of which the following is a. specification.

My present invention relates to certain improvements in devices setforth in an application of George Westinghouse Serial Number 520,039filed September 28, 1909. It is also related to my application SerialNumber 545,957 of even date herewith and it includes certain novelcombinations somewhat analogous to those Shown in the a plication ofGeorge Westinghouse, Serial umber 545,854 of even date herewith.

lVith respect to the general nature of the invention it may be said toresemble the inventions of the above mentioned applications insomuch asit is embodied in a fluid cushion device particularly adapted for use asa spring, which may be used in any relation where two bodies are soassociated that resilient movement is desirable, and especially whereone or the other of the bodies is subject to sudden movements,vibrations, or shocks which it is undesirable to have transmitted to theother of said bodies. Certain features relating to the packin andlubrication of the sl1ding joint of tie cylinders a're applicable in anyrelations where high pressures are to be sustained.

It will be understood that though capable of use in other relations, theinvention has been devised primarily in connection with automobiles, andthe general object in view'has been to embody the principles ofresilient support by means of an elastic-Huid cushion, such as air orgas in a practical, self-contained, air-tight device capable of movementfor compression and extension and adapted to serve as a spring, but

to combine therewith all the desirable fea-y ner tube provided at theinner end with peripheral packing adapted to form a fluid tight joint,and is internally contracted to form a relatively constricted assage, sothat the flow of liquid to and ro between the fixed volume space in theupper cylinder and the variable space in the lower cylinder, is more orless throttled. The fluid within the cylinder consists of a compressiblemedium such as air or other gas in the upper portion, and anincompressible medium, such as oil, glycerin, etc., filling the lowerportion, preferably to a level above the packlng. The throttling effectat the lower end of the plunger cylinder may be rendered asymmetric bymeans of a check valve adapted to remain normally open on thecompression movement of the spring, but to cut off a desired portion ofthe passage upon the extension movement. The normal internal pressure ofthe fluid medium is preferably igh, but for convenience in practicaloperation of an automobile, is preferabl not higher than can be suppliedby an e cient tire pump of the ordinary commercial type. In saidvapplications referred to I have shown a pump adapted to remove fluidfrom the low pressure side of the packing for the sliding joint betweenthe cylinder and plunger, and to force the fluid into the pressurecavity within the cylinder. The pum i referred to is located inside ofthe cyhnder and may be arranged so as to ap )ly a certain degree ofsuction between t e sliding surfaces of the two cylinders and this mayserve in certain cases to pump air into the cylinder as well as tocollect escaping oil. In cases where the pump is of a ca acity adaptedto produce increase of interna pressure, I may provide an adjustablercliet' valve adapted to permit esca. of air when the internal pressureexcee s the desired value.

One of the objects of my present invention is to arrange an internalcompression pump so that its compression or forcing strokes will becoincident with the extension movements of the relatively movablecylinder and plunger so that discharge of fluid into the pressure cavitywithin the device will take place at times when the internal pressure isconsiderably lessened and hence the work to be done by the pump will notbe so great as where the forcing strokes of the 'pum are caused bycompression movements -of te members. It is obviously much easier toforce material into the interior at or near the end of an extensionmovement than when the compression device is fully compressed underextreme load.

Another object of the invention is to arrange the inlet passage wherebyfluid is removed from the low ressure side of the sliding joint so thatt e natural drainage due to gravity will be downward throughout the saidpassage and through the check valve cavities therein, as well as throughthe pump cavity where a pump is used. One of the check valves in suchpassage may be normally located below the level of the liquid within thedevice so that the valve is normali bathed in liquid and therebyprevented rom leaking.

Another object of my invention is to arrange an internal pump operatedby iiow of fluid within the device so as to have its forcing strokecoincide with extension movements of the cylinder and plunger incombination with an external pump and an intermediate check valve insuch manner that the external pump ap lies pressure to the low pressureside of t e sliding joint on compression movements of the device so thatthe forcing Lmovements of the external pump alternate with the forcingmovements of the internal pump.

The internal pump having its forcing stroke coincident with theextension movements of the device may have its intake on the lowpressure side of the main packing or between two packings and where twopackings and a collecting groove are employed the upper packing may be acup leather arranged to scrape oil into the collect-ing groove.

In the drawings Figure 1 is a vertical axial section through one form ofmy device. Fig. 2 is a top plan view of the same. Fig. 3 is a detailedview of a modified form of plunger head containing my invention.

The lower cylinder is hermetically closed at the bottom by a screw head2 which is formed with a drain passage 3 normally closed by screw plug4. The cylinder 1 provides a variable space 5 which is adapted to beincreased or decreased by u yor down movements of the plunger cylin er6. The latter is provided on the upper end with the screw closure 7. Thelowerend is screw threaded at' 8 to a lunger head provided with anexternal pacilring and an internally constricted fluid assage. Thepacking consists of a cup leat er 10 clamped against seat 11 by means ofan annular ring 12. The free edge of the cup leather is preferably cutsquare and is held in close engagement with the inner walls of thecylinder by means of a cone expanding rin 13. The annular spaceadjacent. the free e ge of the cup leather 10 including the spacecontainin the expanding ring 13 is supplied with oi from the an-"creasinr internal (pressure.

nular reservoir 14 by duct 15 passing downward in the rear of seat 11cup leather 10 clamping ring 12 and cone ring 13. There may be a numberof these ducts providing a continuous supply of oil within the spaceadjacent the cup leather where it is held by means of the supplementalpacking 17 arranged below said main packing.

My pump arranged for expelling fluid into the interior during times ofdiminishing internal pressure is mounted upon the plunger head inoperative relation to the constricted path of iluid flow therethrough.This pump has an intake in an annular collecting groove 18 adapted tocollect surplus oil from the sliding joint on the rear side of the cupleather packing. The intake 19 leads downward to valve 20, thencethrough passage 21 to the pump cavity 22 thence downward through valve23 to the exit openings 24 within the pressure cavity of the device. Thevalves are ball valves, spring pressed upwardly as shown in thedrawings, and the pathof the entire passage is such that there is noup-turn where liquid would have to move against the force of gravity.The proportion of parts is preferably such as to bring the lower ballvalve 23 low enough so that it is normally submerged in the oil withinthe device.

By reference to the drawing it will be seen that the pump piston 25 issomewhat similar to piston shown in the other internal pumps of theapplications above referred to, but the arrangement thereof is differentin that the piston stem extends upwardly from the pump cavity and hasrigidly secured thereto the disk 26 which 1n the present case serves thefunction of an asymmetric check valve adapted to permit relatively freeflow of fluid on the compression movements of the device and to restrictthe flow to a predetermined degree upon extension movements therebypreventing the excessive recoil which occurs when no special means forpreventing recoil is employed. This arrangement of the piston and fluidactuated disk causes the piston to make its upward or suction strokeduring compression move` Inents of the device and its downward strokeduring the recoil or extension movements thereof, so that the time ofdischarge of fluid into the device coincides with times of dev Therebeing no upwar ly directe passages in the path of fluid flow betweenlnlet and outlet of the pump, the li uid part of the fluid mediumhandled there y would tend to settle into the inlet of each valve and ofthe pump cavity. From this it results that the valves of the pump pistonwill be sealed by the oil and the tendency will be to pump oil first andthen air.

My internal pump operating as above dc- .scribed may be used alone or ifdesired it very 4 side of passage 21. The pressure from the externalIMLMQ may be used in connection with an external pump such as shown inthe application of George Westinghouse, Serial 170.545,854 of rigidlyconnected with plunger cylinder 6 and spaced apart therefrom so as toform an annular compression space 28, the upper end of the compressioncylinder being utilized as an annular piston for compressing theairwithin said space. The packingfor this annular piston consists of acup leather 35. bearin against the outer cylinder 27 and clamped Ween ascrew ring 36, screwed on to the upper end of cylinder 1 and a clampingring 37 screwed to ring 36. An inlet.check valve conventionallyindicated at 40 is arranged on the cylinder head 7. With thisarrangement extension movements of the spring serve to draw in airthrough the check valve, while return movement compresses it, and whenthe movement is suilicient to produce a sufficient compression the airescapes downward through the joint between the annular'grin 36 and theadjacent wall ofcyliiider 6. T is raises the pressure on the rear sideof the sliding 'oint thereby tending to force oil or air or oth downwardthrough the valve 20.

As the lit of the sliding joint is usually perfect I prefer to providethe outer surface of cylinder 6 with one or more verticalv grooves 41,communicating with the annular collectingy groove 1-8. In the abovedescribed arrangement the external pump coperates with the internal pumpand intermediate valve 20 so as to give a two-stage compressionoperation and the final com pression serves to discharge the fluid intothe compression space within the device during times of decreasingpressure therein in the following manner. vAir is drawn in throughvalve4:0 during any suiciently long extension movement of the device and iscompressed by the succeedin compression movement. It will be note thatduring suchA compression movement the piston V of the internal 'pumpawill be drawn upwardly b. flow of fluid against the under isk 26,thereby uncovering inlet pump taking effect through groove 41 serves toraise the pressure in the collecting groove 18 and in case there is anyoil col the bottom of said oove to force it into the intake 19 of hepump and down through valve 20, thus raising the pressure in the valvechamber, passage 21 and in the punp cavity whenfiassage 21 is uncoveredy e piston, the egree of pressure being dependent` upon the amplitude ofthe move` ments. 'Ehe pump piston being actuated by fluid dow,l beginsits forcing movement as soon as the recoil or extension movement of thedevice starts. downward flow from the ected in i upper cylinder 6 intothe variable compression space 5.- This closes the assage 21 f' at theinstant the pressure from t e outside even, date herewith.' In thelatter case I may arrange an outer or guard cylinder 27 ump begins tofall oli". The downward or orcing movement Aof the pump piston iscompleted as soon as the violence of downward flow of fluid in thedevice is sufficient to overcome the internal pressure which decreasesas the recoil or extension movement v;

pro esses.

e arrangements for charging the device with oil and compressed air arepreferably 'flccated in head 7 of cylinder 6. As

shown in Fig. 1, an inlet tube 60 extends down a desired distance, vsothat its outlet orifice 61 is at or about the desired level of theliquid to be used. The passage of air or liquid through this tube iscontrolled by a needle valve indicated at 62. As indicated in Fig. 2,there is a passage 64 leading from the needle valve chamber to an inletcheck valve 65, which communicates with a screw threaded opening, towhich may beconnected supply pipes for oil or compressed air. Incharging the device oil may be introduced either by removing needlevvalve 62 and lsubstituting an oil supply pipe, or needle valve 62 may bemerely loosened and the oil supplied through the opening 66 and checkvalve 65. After oil has been charged into the device to a suitableheight, which is preferably above the level of the orifice 61 of pipe60, the compressed airis introduced through 66,65, 64, 60, until theinternal'fpressure is suiicientgto support the desire th positionindicated at supp y is then detached and-surplus oil blown out throughpipe 60, until theescape of air indicates that its orifice has beenuncovered by lowering of the level of the liquid. -The needle valve 62and the plug 67 are then screwed tight and the device is in conditionfor use.A

Where the pumping capacity of the pump described above is suliicient toraise the iiiternal pressure of the device, undue raise of pressure maybe prevented by an automatic relief valve, which is diagrainmaticallyindicated in Fig. 2 as comprising a plug valve 70, closing spring 71,and screw adjusting means 72 for adjusting the initial pressure of thespring to thereby predeterminethe maximum internal pressure, which maybe maintained in the device.` The above described device is provided atboth ends with journals 80, 80, adapted to engage pivots of a universaljoint comprising pivots arranged at ri ht angles to each other and acoperatiiig racket attached to one of the members to be cushioned bysaid device.

In Fig. 3 I have shown a modified arrangement which differs from that ofFig. 1 in that the valve disk is free to slide on the pump stem., twovalves are used in seload with the partsza proximately in ig.1.' The air.l

y, zo

quence below the pump piston in the exit passage thereof and thedownward movements of the piston are assisted by a spring. The advantagein using such a spring is that the more violent upward tiow of fluid onthe compression movement of the device may used to store up energy bycompressing the spring so that such energy may beavailable to assist thedownward flow of fluid in forcing the expelling movement of the pumppiston, during recoil or extension movements of the device. In said Fig.3 the main cylinders 1 and G and the external parts connected therewithmay be the same as shown in Figs. l and 2, the object being toillustrate the modified arrangement of the plunger head, pump stem andvalve disk. The plunger head 111 is screw threaded to the lower end ofcylinder" (l and is formed witha downward extension 112 having suitablepackings secured upon the screw threaded exterior thereof and affordinginteriorly a constricted passage for flow of the fluid to and frobetween the variable volume space 5 in cylinder 1 and a fixed volumespace in cylinder 6. As shown there are two main packings and asupplemental packing. The main packings are similar and comprise cupleathers 113, 114 held against suitable seats by clamping rings 115, 116respectively. The free edges of the cup leathers are preferably cutsquare and are held in close engagement with the wall of the outercylinder by means of cone eX- anding rings 117, 117 spring pressed in aIdirection parallel to the axis of the device so as to afford a wedgingexpanding action upon the interior edges of the cup leathers. Theyielding spring pressure for these rings is preferably provided by aseries of small springs 118, 118 distributed at suitable points aboutthe periphery. These give an even pressure at all points about thecircumference. The upper cup leather 113 serves to wi e surplus oil fromthe walls' of the cylinder and-to collect the same within the annularcollecting groove 119, whence it may be drawn through symmetricallyarranged ducts 120, 120 into the pump cavity whenever the piston 121 iswithdrawn sufliciently to uncover said ducts. A circumferential groove111a is formed in the outer surface of plunger head 111 so that theouter and inner sections of ducts 120 will be in communication whatevermay be their angular relation when clamping ring 115 is screwed tightagainst cup leather 113.

The upwardly extending piston stem 122 carries the valve disk 123 whichis capable of relative movement along said stem but which normally tendsto remain in the uppermost position by reason of the action of s )ring124 which is interposed between said isk and a collar 126 on the pumpstem.

The pump piston is normally subject to l the downward pressure of spring127 seated in groove 128 in the block 129 secured to the end of the pumpstern. The spring is secured at the upper end by encircling a downwardlyprojecting seat 130 on bridge 131. The exit. passage from the pumpcavity is closed by a double ball valve consisting of lower ball 132spring pressed upwardl against seat 133 and a second smaller bal 13-1spring pressed upwardly against seat 135 by means of spring 136 restingupon the lower ball 132. Thisdouble valve affords double securityagainst escape of Huid from the pressure cavity of the device.

It will be understood that the springs 124 and 127 for the pump stem andvalve disk may be selected to suit the conditions and if desired may bmade so light as to afford little or not obstruction to the movements ofeither pump stem or disk. In the latter case they will serve merely tocause the parts to tend to seek the position shown in Fig. 3 when notdisplaced therefrom by fluid How and other forces acting thereon.

Various features of my invention are adapted for use in other relationswhere the conditions and functions to be served are similar, as, forinstance, in other devices wherein a sliding joint is required tosustain great pressures without leaking; also 95 they may be used as asupplement to or substitute for and may be supplemented or substitutedby features set forth in the application of Richard Liebau, Serial No.468,762, filed December 22nd, 1908.

While I have herein fully shown and described, and have pointed out inthe appended claims certain novel features of construction, arrangement,and operation which characterize my invention, it will be under- 105stood by those skilled in the art that various omissions, substitutions,and changes in the forms, proportions, sizes, and details of the deviceand of its operation, may be made without departing from my invention.

I claim:

1. A cushion device, comprising relatively movable members forming aclosed chamber, in combination with an internal comression pump having acompression cham- 115 lier carried .by one of said movable members, anda piston having its strokes coincidentwith the extension movements ofsaid relatively movable members.

2.k A cushion device comprising relatively 120 movable members forming aclosed chamber, in combination with an internal pump havin a compressionchamber carried by one o said movable members, and a piston operated bypower derived through relative 125 movement of said members and arrangedto decrease the fall of pressure within said closed chamber coincidentwith periods of decreased pressure therein.

3. A cushion device comprising a cylinder 133 and a plunger adapted forrelative movement, in combination with lan internal pump having acylinder carried by the plunger, and a piston operated by power derivedthrough relative movement of said plunger and cylinder and arranged toincrease the pressure within the pressure cavity of said device duringthe extensionV movements of said cylinder and plunger.

4. A cushion device comprising a cylinder and a plunger adapted forrelative movement, in combination with an internal pump arranged toincrease the pressure within the pressure cavity of said device at timesof decreasing pressure therein.

5. A cushion device comprising relatively movable members forming aclosed chamber, in combination with an internal compression pumparranged to discharge fluid into said chamber, and automatic meansoperated by flow of liquid within the device for causing said pump todischarge coincidently with times of decreasing pressure in saidchamber.

6. A cushion device comprising relatively movable members forming aclosed chamber, in combination with a compression pump and non-positiveautomatic means operated by 'the flow of fluid resulting fromcompression and extension movements of said relatively movable membersfor discharging iuid into said chamber automatically and coincidentlywithv the times of decreasing pressure therein.

7. The combination with members having a sliding joint therebetween andforming a chambered device capable of movement for compression andextension, of liquid and gaseous fluids within the chamber, and a pumpwithin said chamber for transferring liquid from said joint to saidchamber arranged to discharge during the extension movements of thedevice.

8. A cushion device comprising relatively movable members forming achamber and having a sliding joint therebetween to permit variation ofthe volumetric capacity thereof, liquid and gaseous fluids within saidchamber, and means for automatically forcing escaped fluid into saidchamber during the extension :movements of the device.

9. A cushion device comprising relatively movable members forming achamber and having a sliding joint therebetween to permit variation ofthe volumetric capacity thereof, liquid and gaseous fluids within saidchamber, and means for forcibly returning the escaped Huid into saidchamber during the extension movements of the device.

10. A cushion device comprising in combination, two cylindersconcentrically arranged and secured to a head member, a cylinderprovided with one closed end and arranged to slide between said twocylinders, a packing for the sliding joint between the inner of said twocylinders, and a -pump within the chamber formed by said two in nercylinders for applying suction to said sliding joint on the rear or lowpressure side of said packing, and means for causing said pump todischarge during the extension movements of the device.

.11. In a cushion device telescopic cylinders, a packing for the slidingjoint between said cylinders, a compressible Huid Within said cylinders,sealing liquid for said joint, and a pump adapted to withdraw liquidfrom the low pressure side of said packing and to force the same intothe interior of said device during the extension Strokes 'of said'cylinders.

Signed at New York in the county of' New York and State of New York this14th day of February A. D. 1910.

RICHARD LIEBAU.`

Witnesses:

GEORGE C. DEAN, IRVING M. OBRIEGHT.

